linux-kernel - Re: [PATCH 1/2] libnvdimm/security: 'security' attr never show 'overwrite' state

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Date:   Mon, 3 Aug 2020 14:10:10 -0700
From:   Jane Chu <jane.chu@...cle.com>
To:     Dave Jiang <dave.jiang@...el.com>, dan.j.williams@...el.com,
        vishal.l.verma@...el.com, ira.weiny@...el.com, jmoyer@...hat.com,
        linux-nvdimm@...ts.01.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] libnvdimm/security: 'security' attr never show
 'overwrite' state

Hi, Dave,

On 8/3/2020 1:41 PM, Dave Jiang wrote:
> On 7/24/2020 9:09 AM, Jane Chu wrote:
>> Since
>> commit d78c620a2e82 ("libnvdimm/security: Introduce a 'frozen' 
>> attribute"),
>> when issue
>>   # ndctl sanitize-dimm nmem0 --overwrite
>> then immediately check the 'security' attribute,
>>   # cat 
>> /sys/devices/LNXSYSTM:00/LNXSYBUS:00/ACPI0012:00/ndbus0/nmem0/security
>>   unlocked
>> Actually the attribute stays 'unlocked' through out the entire overwrite
>> operation, never changed.  That's because 'nvdimm->sec.flags' is a bitmap
>> that has both bits set indicating 'overwrite' and 'unlocked'.
>> But security_show() checks the mutually exclusive bits before it checks
>> the 'overwrite' bit at last. The order should be reversed.
>>
>> The commit also has a typo: in one occasion, 'nvdimm->sec.ext_state'
>> assignment is replaced with 'nvdimm->sec.flags' assignment for
>> the NVDIMM_MASTER type.
> 
> May be best to split this fix to a different patch? Just thinking git 
> bisect later on to track issues. Otherwise Reviewed-by: Dave Jiang 
> <dave.jiang@...el.com>

Sure. I take it you meant to separate the typo fix from the change that 
tests the OVERWRITE bit first?

Regards,
-jane